Can you guess what this spike in the data is?
Surprisingly, it is not an earthquake, but the calving of a glacier near one of the stations we set up, station BHIKE. The glacier was about 1 kilometer away, but it only took the shock wave from the impact about 0.2 of a second to reach the station. The whole incident from start to finish only took a measly 10 seconds. The coolest part of the whole event was that we were standing on top of the glacier and felt when the piece of falling ice hit the ground. Unfortunately, the park ranger wouldn't let us go over to the edge to look at the piece of ice that fell.
In the figure below, the start of the p-waves and s-waves are labeled, along with what we think is the start of the ice cracking. The surface wave, which is the largest spike on the figure is what we got to feel on top of the glacier.